cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A350717 a(n) = 4*a(n-1) - n - 1, for n > 0, a(0) = 1.

Original entry on oeis.org

1, 2, 5, 16, 59, 230, 913, 3644, 14567, 58258, 233021, 932072, 3728275, 14913086, 59652329, 238609300, 954437183, 3817748714, 15270994837, 61083979328, 244335917291, 977343669142, 3909374676545, 15637498706156, 62549994824599, 250199979298370, 1000799917193453, 4003199668773784
Offset: 0

Views

Author

Paul Curtz, Feb 03 2022

Keywords

Comments

Last digit (using 0 to 9) is of period 10: repeat [1, 2, 5, 6, 9, 0, 3, 4, 7, 8].

Crossrefs

Cf. A007583 (first differences), A014825, A160156.

Programs

  • Mathematica
    LinearRecurrence[{6, -9, 4}, {1, 2, 5}, 28] (* Amiram Eldar, Feb 03 2022 *)
  • PARI
    a(n) = if (n, 4*a(n-1) - n - 1, 1); \\ Michel Marcus, Feb 03 2022
    
  • Python
    print([(2**(2*n+1) + 3*n + 7)//9 for n in range(30)])
    # Gennady Eremin, Feb 05 2022

Formula

a(n) = (2^(2*n+1) + 3*n + 7)/9.
a(n) = 6*a(n-1) - 9*a(n-2) + 4*a(n-3), n >= 3.
a(n) = a(n-1) + A007583(n-1).
a(n) = 2*a(n-1) + A014825(n-1).
G.f.: (-2*x^2 + 4*x - 1)/((x - 1)^2*(4*x - 1)). - Thomas Scheuerle, Feb 03 2022
a(n) = -1 + 5*a(n-1) - 4*a(n-2), n >= 2.
a(n) = 1 + A160156(n-1), n >= 1.

Extensions

More terms from Michel Marcus, Feb 03 2022

A360967 Array T(n,m) = (2^(m*(2*n+1))+1)/(2^m+1) read by antidiagonals.

Original entry on oeis.org

3, 13, 11, 57, 205, 43, 241, 3641, 3277, 171, 993, 61681, 233017, 52429, 683, 4033, 1016801, 15790321, 14913081, 838861, 2731, 16257, 16519105, 1041204193, 4042322161, 954437177, 13421773, 10923, 65281, 266354561, 67662254017, 1066193093601, 1034834473201, 61083979321, 214748365
Offset: 1

Views

Author

R. J. Mathar, Feb 27 2023

Keywords

Examples

			The array starts in row n=1 and column n=1 as
      3      13      57     241
     11     205    3641   61681
     43    3277  233017 15790321
    171   52429 14913081 4042322161
		

Crossrefs

Cf. A007583 (col 1), A299960 (col 2).
Previous Showing 101-102 of 102 results.